Omega-3s, Coenzyme Q10 Support Oocyte Quality, Fertility in Mares

Mares have a limited number of opportunities to carry a foal each year. Because of this time crunch, fertility issues often stir angst and disappointment among broodmare managers.

Karen Wolfsdorf, D.V.M., a reproductive specialist from Hagyard Equine Medical Institute in Lexington, Kentucky, presented on early embryo loss (EEL) during the 69^th Annual Convention of the American Association of Equine Practitioners (AAEP) held in December 2023.^*

“A high rate of EEL in mares may be related to age, oocyte [egg] abnormalities, embryonic defects, or the oviductal or uterine environment,” she said.

She added that an age-associated decline in oocyte quality is a primary factor in reduced fertility in older mares, and further studies identified that oocyte quality decreases due to mitochondrial changes.

Mitochondria are organelles within the cell referred to as “powerhouses” because they produce a great deal of energy for cellular functions.

In 2020, veterinary researchers from Colorado State University also recognized the importance of mitochondria in supporting oocytes and early embryos.^** They hypothesized that omega-3 fatty acids would affect mitochondrial number and function. Thus, mares were randomized to receive either a base diet of grass and alfalfa hay with or without a mixture of omega-3 fatty acids and antioxidants for six weeks. Oocytes were collected from all mares and mitochondria number and quantity of mitochondrial DNA (genetic material in the mitochondria) were measured. The oocytes were then fertilized, and embryo development assessed. EO-3 is a concentrated marine-derived source of the omega-3 fatty acids DHA and EPA, two of the most biologically active omega-3s.

The research team found:

• Mitochondrial oocyte number was lower in the control group;
• Mitochondrial DNA was higher in the control group presumably due to “a compensatory mechanism for mitochondrial dysfunction;” and
• Embryo development was lower in the control group.

The research team therefore concluded that “mare diet altered oocyte mitochondrial number and function, as well as a potential for development into a blastocyst [embryo], indicating that it is capable of affecting the oocytes’ quality and developmental capacity.”

In a human study, researchers looked at the effect of the antioxidant coenzyme Q10 on fertility outcomes of women undergoing assisted reproductive techniques.⁺ They reviewed data from five clinical studies and found that supplementing women with coenzyme Q10 may increase clinical pregnancy rates.

“Supplementing mares with omega-3 fatty acids, including the DHA and EPA in EO-3, and antioxidants, such as coenzyme Q10 found in Nano-Q10, may benefit reproductive efficiency in the early stages of embryo development. This benefit may result from supporting the metabolic function of embryos or quelling inflammation, particularly in older mares,” said Kathleen Crandell, Ph.D., a nutritionist at Kentucky Equine Research. “Coenzyme Q10 is an effective free radical quencher and helps boost cellular energy through ATP synthesis. Both functions are essential to healthy early embryonic development.”

^*Wolfsdorf, K. 2023. How to improve early embryonic loss. American Association of Equine Practitioners Proceedings 69:25-31.

 ^**Catandi, G. Y. Obeidat, J. Stokes, A.J. Chocco, T. Chen, and E. Carnevale. 2020. Maternal diet can alter oocyte mitochondrial number and function. Journal of Equine Veterinary Science 89.

 ⁺Florou, P., P. Anagnostis, P. Theocharis, M. Chourdakis, and D.G. Goulis. 2020. Does coenzyme Q10 supplementation improve fertility outcomes in women undergoing assisted reproductive technology procedures? A systematic review and meta-analysis of randomized-controlled trials. Journal of Assisted Reproduction and Genetics 37(10):2377-2387.